Asthma in Elementary School Children is Associated with Proximity to Concentrated Animal Feeding Operations

Joel N. Kline, MD
College of Medicine, University of Iowa
P30ES05605

Elementary school children may be at higher risk for developing asthma if their school is near a large­scale livestock farm known as a concentrated animal feeding operation (CAFO) according to research published in the June issue of Chest, the journal of the American College of Chest Physicians. Joel Kline, an NIEHS-supported scientist at the University of Iowa Environmental Health Sciences Research Center, studied children at two rural Iowa elementary schools. The study school was a half mile from a CAFO and the control school was more than 10 miles away from any large-scale agricultural facility. Almost 20 percent of children at the study school had a physician-diagnosis of asthma compared to about 7 percent of the control school kids. When Kline broadened the definition of asthma to include asthma-like symptoms or asthma medication use, there was still more than a two-fold difference in the asthma prevalence. The overall rate of physician diagnosed asthma in Iowa is 6.7 percent.

CAFOs are controversial because of recurring problems with odor, ground and surface water contamination, and noise. According to Kline, they emit irritants and inflammatory substances that affect the health of workers at the facilities and are a detriment to air quality in surrounding communities; thus causing him to investigate whether there was a connection between CAFOs and increased rates of asthma among children in rural areas.

The paper urges caution on the interpretation of the results. Possible confounders of the study could be differences in smoking rates among the children’s parents, pet ownership, residence on a farm, asthma diagnosis by different physicians, etc. The authors conclude that more research is necessary on the effects of CAFOs on communities, not just on workers or people in the direct vicinity of the facilities.

Citation: Sigurdarson ST, Kline JN. School proximity to concentrated animal feeding operations and prevalence of asthma in students. Chest. 2006 Jun;129(6):1486-91.